Just got an A7Rii body to complement my A6500 and have some questions to speed up the learning curve: (1) When dropping below ISO100 what sort of drop off in picture quality does that yield? Should I ...

Better color rendering, more detail, less noise and shallower dof when desired. Basically all aspects of what makes a quality photo. Here's a good comparison tool as an example: https://www.dprevie ...